The title compound, C23H23NO, is the product of a tandem transformation of the double Mannich base bis(1-oxo-1,2,3,4-tertrahydro-2-naphthoylmethyl)amine hydrochloride in HBr solution upon heating. The tetrahydropyridine ring has a non-symmetrical half-chair conformation, whereas the cyclohexadiene and cyclohexene rings adopt non-symmetrical half-boat conformations. The dihedral angle between the planes of the terminal benzene rings is 62.85 (6)°. The N atom has a trigonal–pyramidal geometry [sum of the bond angles = 332.4 (3)°]. In the crystal, molecules form  chains via weak non-classical C—H⋯N hydrogen bonds. The chains are stacked along the b axis.